Anesthesia can be delivered to a patient either intermittently, with rather complicated valving, as a patient alternately inhales and exhales, or it may be administered continuously. One commercial circuit for the continuous application of anesthesia is sometimes known as a coaxial circuit. In accordance with this known circuit there is an exterior corrugated, flexible tube connected at the patient end to an endotracheal tube or a mask, and connected at the other end to an exhaust, preferably a scavenger system. An inner flexible tubing, generally non-corrugated, terminates at the patient end within the outer tube, generally near the end thereof, and at the opposite end exits laterally of the outer tube. Anesthesia gas is provided to the lateral end. The gas so supplied generally comprises an anesthetic gas mixed with air or oxygen. As the patient inhales he receives gas from the inner tube. When he exhales he dispells used anesthesiology gas into the exhaust system, and a certain amount of fresh gas also is bypassed into the exhaust system.
In the known coaxial circuit, as in most anesthetic circuits in use today, connections usually comprise press fits of plastic parts. Such connections usually are satisfactory, but they can come apart with considerable danger to the patient, and some danger to the surgical team. Furthermore, such fittings are often rather hard to assemble properly.